Experimental Study on Internal One-Dimensional Heat Conduction Law of Granite under High-Temperature Thermal Shock

The deteriorating effect of heat on rocks' physical and mechanical properties is determined by a combination of factors such as the structure, mineral composition, and mineral distribution of the rocks. A high-temperature thermal shock test is conducted to address the one-dimensional heat conduction problem of semi-infinite objects experiencing high-temperature thermal shock in engineering. The change rule of temperature field, heating rate, and temperature gradient field in the process of thermal shock are analyzed, the thermal shock factor is introduced to quantitatively characterize the degree of heat damage to the rock in the process of high-temperature thermal shock, and the influence of heat source temperature and medium on the heat transfer of granite is discussed. The experimental results show that: The temperature changes within the granite at different thermal shock temperatures can be divided identically into three stages: rapid heating, slow heating, and temperature stabilization. Influenced by the non-homogeneity of granite, the distribution of the temperature field and temperature gradient field in granite under high-temperature thermal shock are disordered, and the degree of disorder of the temperature gradient field is higher than that of the temperature field. During high-temperature thermal shock, the granite's distribution of thermal shock factors is significantly non-homogeneous, and its peaks are dynamically moving. At 100°C, since water has a greater convective heat transfer coefficient than silicone oil at that temperature, the temperature, rate of warming, and temperature gradient within the granite have a greater peak and enter the stabilization phase earlier when using water as the heat source medium compared to silicone oil as the heat source medium.